A large number of methods and systems are known for optically inspecting articles. For example, Dotan et al. U.S. Pat. No. 5,216,479 discloses a system for optically inspecting objects, particularly printed circuit boards, by projecting a beam of light onto one face of the object, and sensing reflected light reflected from that face and fluorescent light induced at that face, such sensed light being then used to indicate defects in the respective face of the object; the described system also transmits the light through the object and senses the transmitted light at the opposite face of the object for detecting defects in plated through-holes in the printed circuit board. Published European Patent Application 92114182.6 also discloses an optical inspection method and system utilizing both reflected light and transmitted light for detecting defects. The systems in both of the above patents are based on a scanning technique wherein the light beam, e.g., a laser beam, is caused to scan the object being inspected.